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United States Patent |
5,619,739
|
Kawabata
|
April 8, 1997
|
Diopter correcting apparatus
Abstract
This specification discloses an apparatus in which data regarding the
proper lens positions of a diopter correcting lens when an observer is
wearing spectacles and when the observer is not wearing spectacles are
pre-stored in a memory circuit, the presence or absence of the spectacles
is detected by a detecting circuit for detecting the state of an anterior
eye part, the data in the memory circuit are extracted in conformity with
this state, and the diopter correcting lens is moved on the basis of these
data.
Inventors:
|
Kawabata; Takashi (Yokohama, JP)
|
Assignee:
|
Canon Kabushiki Kaisha (Tokyo, JP)
|
Appl. No.:
|
454086 |
Filed:
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May 30, 1995 |
Foreign Application Priority Data
Current U.S. Class: |
396/382 |
Intern'l Class: |
G03B 013/02 |
Field of Search: |
354/410,62,219
351/210
396/51,18,373,382
|
References Cited
U.S. Patent Documents
4300818 | Nov., 1981 | Schachar | 351/210.
|
4828381 | May., 1989 | Shindo | 354/62.
|
5182443 | Jan., 1993 | Suda et al. | 354/219.
|
5335035 | Aug., 1994 | Maeda | 354/219.
|
Foreign Patent Documents |
63-206731 | Aug., 1988 | JP.
| |
4138431 | May., 1992 | JP.
| |
4138432 | May., 1992 | JP.
| |
Primary Examiner: Perkey; W. B.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper & Scinto
Claims
What is claimed is:
1. A diopter correcting apparatus comprising:
optical lens means for performing diopter correction;
detecting means for detecting whether an observer is wearing corrective
lenses;
memory means storing therein data regarding a position of said optical lens
means in accordance with a result of the detecting performed by said
detecting means; and
driving means for driving said optical lens means on the basis of the data
stored by said memory means.
2. A diopter correcting apparatus according to claim 1, wherein said memory
means further stores therein first data regarding the position of said
optical lens means in a state in which an observer is wearing spectacles,
and second data regarding the position of said optical lens means in a
state in which the observer is not wearing spectacles.
3. A diopter correcting apparatus according to claim 2, wherein said
detecting means detects whether the observer is wearing corrective lenses.
4. A diopter correcting apparatus according to claim 3, wherein said
driving means drives said optical lens means on the basis of the first
data when said detecting means detects that the observer is wearing
corrective lenses.
5. A diopter correcting apparatus according to claim 3, wherein said
driving means drives said optical lens means on the basis of the second
data when said detecting means detects that the observer is not wearing
corrective lenses.
6. A diopter correcting apparatus according to claim 1, wherein the
corrective lenses detected by said detecting means are spectacles.
7. A diopter correcting apparatus according to claim 1, wherein the
corrective lenses detected by said detecting means are contact lenses.
8. A diopter correcting apparatus according to claim 3, wherein the
corrective lenses detected by said detecting means are spectacles.
9. A diopter correcting apparatus according to claim 3, wherein the
corrective lenses detected by said detecting means are contact lenses.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical apparatus having diopter correcting
means, and particularly to an optical apparatus having diopter correcting
means suitable, for example, for a camera, binoculars or the like which is
adapted to detect whether an observer wears spectacles or contact lenses
and to automatically appropriately set the diopter of an optical system
into which the observer looks.
2. Related Background Art
Generally, the correction of the diopter of an optical apparatus such as
the finder of a camera or binoculars has been accomplished by manually
moving a portion of an eyepiece optical system to adjust it to a position
one can readily see.
Also, Japanese Laid-Open Patent Application No. 63-206731 proposes a finder
apparatus adapted to detect a value related to the refractive power of the
eye of an observer looking into a finder by an eye refractometer, and to
effect the correction of the diopter of a finder optical system in
conformity therewith.
On the other hand, as an apparatus having a similar optical construction, a
camera having a visual axis detecting unit is proposed in Japanese
Laid-Open Patent Application No. 4-138431 and Japanese Laid-Open Patent
Application No. 4-138432.
These publications propose a camera having a visual axis detecting unit
adapted to detect by a spectacle detecting portion provided in a portion
of the camera whether a photographer is using spectacles, and to adjust
the construction of light receiving means on the basis of a signal from
the spectacle detecting portion.
In the above-described apparatus wherein diopter correction is manually
effected, each time a state in which observation is done (hereinafter
simply referred to as the observation state), such as whether the observer
is observing while wearing spectacles or contact lenses or observing by
the naked eye, changes, it is necessary to manually readjust the diopter,
and this has led to the problem that operation is cumbersome.
Also, the finder apparatus of the aforementioned Japanese Laid-Open Patent
Application No. 63-206731 is effective when highly accurate diopter
correction is effected to many and unspecified observers, but it is too
large-scale in apparatus construction as an apparatus for use by ordinary
substantially limited observers. Particularly it has been difficult to
apply it to an apparatus to the portability of which importance is
attached.
Generally, to an observer who usually wears spectacles, there has been the
problem that when conditions such as temperature and humidity are bad or
suddenly change, the spectacles sometimes become clouded and any other
apparatus than an apparatus which enables observation to be readily made
in other observation state (for example, a state in which the observer has
taken off the spectacles) is difficult to use.
SUMMARY OF THE INVENTION
The present invention has as its object the provision of an optical
apparatus having diopter correcting means for detecting the observation
state of an observer looking into an optical system, and moving at least a
portion of the optical system on the basis of the observation state to
thereby achieve the simplification of the whole apparatus and yet enable
appropriate diopter correction to be readily effected even in a different
observation state.
The present invention is characterized in that data regarding the proper
lens positions of a diopter correcting lens when the observer is wearing
spectacles and when the observer is not wearing spectacles are pre-stored
in a memory circuit, the presence or absence of the spectacles is detected
by a detecting circuit for detecting the state of an anterior eye part,
the data in the memory circuit are extracted in conformity with this
state, and the diopter correcting lens is moved on the basis of these data
.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view showing the essential portions of Embodiment 1
of the present invention.
FIG. 2 is an optical illustration of an image formed on the light receiving
surface of a detecting unit.
FIG. 3 is an illustration showing the positional relations among the
element of FIG. 2.
FIG. 4 is an illustration of diopter correcting means.
FIG. 5 is a schematic view showing the essential portions of Embodiment 2
of the present invention.
FIG. 6 is a schematic view showing the essential portions of a finder
optical system.
FIG. 7 is a developed illustration showing the optical path of the
detecting unit when an observer is observing by the naked eye.
FIG. 8 is a developed illustration showing the optical path of the
detecting unit when the observer is using spectacles.
FIGS. 9A, 9B and 9C are illustrations of a refraction image formed on an
image sensor and output intensity obtained from the reflection image.
FIG. 10 is comprised of FIGS. 10A and 10B showing flow charts when
detecting the observation state.
FIG. 11 is an enlarged illustration of portions of Embodiment 3 of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a schematic view showing the essential portions of Embodiment 1
of the present invention applied to a single-lens reflex camera. FIG. 2 is
an optical illustration of an image formed on the light receiving surface
of the detecting unit of FIG. 1, FIG. 3 is an illustration showing the
positional relations among the elements of FIG. 2, and FIG. 4 is an
illustration of diopter correcting means according to the present
invention.
In FIG. 1, the reference numeral 1 designates a photo-taking lens for
forming an object image, and the reference numeral 5 denotes a quick
return mirror for changing over the optical path from the photo-taking
lens 1. The reference numeral 2 designates a shutter (a focal plane
shutter or the like) for controlling the amount of exposure light to film
3.
During exposure, the quick return mirror 5 is retracted upwardly (out of an
exposure optical path) and a beam of light from the photo-taking lens 1 is
directed onto the surface of the film 3 through the focal plane shutter 2
and forms an object image thereon.
The reference numeral 6 denotes a focusing screen disposed conjugately with
the film 3 with respect to the beam of light from the photo-taking lens 1
through the quick return mirror 5.
During non-exposure, the quick return mirror 5 is positioned downwardly,
i.e., in the beam of light from the photo-taking lens 1 (the position
indicated by solid line in FIG. 1), and the beam of light is directed onto
the surface of the focusing screen 6 and forms an object image thereon.
The reference numeral 10 designates a pentagonal prism which reflects and
deflects the beam of light from the focusing screen 6 so that the object
image on the surface of the focusing screen 6 may be observed as a
positive erect image through eyepieces 8 and 9 which will be described
later.
The eyepieces 8 and 9 direct the beam of light from the pentagonal prism 10
to an observer's eyeball. The eyepieces 8, 9 and the pentagonal prism 10
each constitute an element of a finder optical system (an optical system).
The observer observes the finder image from an observation position (eye
point) 7 through the finder optical system.
The reference numeral 15 denotes a motor for diopter correction, and the
reference numeral 16 designates a screw portion. The screw portion 16
threadably engaged with a portion of a holding member 9a for holding the
eyepiece 9 is rotated by the motor 15, whereby the eyepiece 9 is moved in
the direction of the optical axis to thereby adjust the diopter of the
finder optical system. The motor 15 for diopter correction and the screw
portion 16 each constitute an element of a driving unit 17.
The reference numeral 20 designates a light source having infrared light
emitting diodes 20a and 20b which may, for example, be iRLED's. The
reference numeral 21 denotes a light divider for reflecting part of
reflected light from the observer's eyeball side and dividing it from the
optical path of the finder optical system when a beam of light (a beam of
infrared light) from the light source 20 is applied to the observer's
eyeball side.
The reference numeral 22 denotes an imaging lens for directing the beam of
infrared light from the light divider 21 onto the light receiving surface
54a of an image sensor 54 and forming a reflection image regarding the
eyeball. The reflection image comprises a reflection image from the
observer's pupil illuminated by the beam of light from the light source
20, positive reflection images of the infrared light emitting diodes 20a
and 20b of the light source from the observer's eyeball or spectacles, or
other corrective lenses.
The reference numeral 23 designates a detecting unit having the image
sensor 54, the imaging lens 22, the light divider 21, the light source 20,
etc. The detecting unit 23 detects the observer's observation state by the
use of various reflection images formed on the light receiving surface
54a.
The reference numeral 18 denotes a control circuit including a memory unit.
The control circuit obtains in advance data for correcting the diopter of
the finder system, specifically the data of the positions at which the
diopter correcting lens 9 should be when the observer wears spectacles and
when the observer does not wear spectacles, in a manner which will be
described later, and stores the data therein.
The detecting unit 23, the driving means 17 and the memory unit 18 together
constitute an element of diopter correcting means.
In FIG. 2, the iRLED 20a of the light source 20 applies infrared light
toward the observer side, i.e., toward the eyeball 25. This beam of light
applied toward the observer side is reflected, for example, by the surface
of the eyeball 25 and forms a virtual image 26, and a beam of light based
on this virtual image 26 is directed to the image sensor 54 through the
imaging lens 22, and the virtual image 26 is formed on the light receiving
surface 54a of the image sensor 54 by the imaging lens 22.
The iRLED 20a is disposed so that the principal ray 28 of the beam of light
forming the image on the light receiving surface 54a may have an
inclination 8 with respect to the optical axis 22a of the imaging lens 22.
Also, as shown in FIG. 3, the iRLED 20b is disposed symmetrically with the
iRLED 20a with respect to the optical axis 22a of the imaging lens 22 and
illuminates the eyeball 25 so that the detection of the reflection image
by the detecting unit 23 can be correctly effected even if the center of
the eyeball 25 deviates a little from the optical axis 22a.
In the present embodiment, by the construction as described above, the beam
of light from the light source 20 is applied to the observer side (the
eyeball and the portion around it), and by the use of the reflected light
from the observer side, the observer's observation state is detected by
the detecting unit 23. The control circuit 18 selects one datum from among
the data pre-stored in the memory unit on the basis of a signal from the
detecting unit 23, for example, zero (such a datum which will cancel the
present diopter correction) or a datum such as a second preset value, and
uses this selected datum to drive the eyepiece 9 by the driving unit 17
and effect the correction of the diopter of the finder optical system.
The operation of the diopter correcting means in the present embodiment
will now be described with reference to FIG. 4. In FIG. 4, the reference
numeral 50 designates a mono-multivibrator which receives a trigger signal
from a timer circuit 75 and outputs a pulse signal.
The pulse signal from the mono-multivibrator 50 is amplified by an
amplifier 51 and turns on and off the iRLEDs 20a and 20b of the light
source 20.
The image sensor 54 is driven by a drive control circuit 55 so as to be
operatively associated with the light source 20, and picks up the
reflection image of the light source passed through the observer's eyeball
or spectacles and outputs an image signal.
The reference numeral 57 denotes an image measuring unit which obtains the
image signal from the image sensor 54 through an amplifier 56 and measures
the spacing between the two reflection images of the iRLEDs 20a and 20b.
The reference numeral 58 designates a comparator which compares the
measured value by the image measuring unit 57 with a predetermined value,
and if the spacing between the two reflection images is greater than a
predetermined distance, judges that the position at which the reflection
has taken place is near and the observer is using spectacles, and if the
spacing is small, judges that the position at which the reflection has
taken place is far and the observer is observing by the naked eye. The
details of this will be described later. In conformity with the judged
observation state, the comparator 58 outputs a High or Low signal. Here,
it outputs Low for the naked eye, and outputs Low when the observer wears
spectacles.
The signal from the comparator 58 is inputted to an AND gate 67 through the
switch circuit 63, AND gate 66 and NOT gate of a memory unit 80.
The memory unit 80 receives the signal from the comparator 58 and one of
latch circuits 61 and 62 is selected by the switch circuit 63. On the
basis of data pre-stored in the selected latch circuit 61 or 62, the motor
15 is controlled through an amplifier 64, whereby the diopter correcting
lens is moved.
The storage of the movement data of the diopter correcting lens 9 will now
be described. This is an operation performed before actual photographing.
For the storage of data into the memory unit 80, a switch 60 is first
operated to make the input signals to AND gates 66 and 67 High. Thereby,
the output of one of the AND gates 66 and 67 becomes High or Low in
conformity with the signal from the comparator 58, i.e., the observation
state.
In the latch circuit 61, 62 on that side on which the signal from the AND
gate 66, 67 has become High, data are changed by the operation of the
operating portion 59. At this time, by the observer operating the
operating portion 59, the motor 15 is controlled through the latch circuit
61 or 62, the switch circuit 63 and the amplifier 64, whereby the diopter
correcting lens is moved so that appropriate diopter may be obtained in
the observation state. Thereafter, the switch 60 is operated to make the
inputs of the AND gates 66 and 67 Low. Thus, the data at this time (the
absolute position of the lens 9, the amount of driving of the motor 15,
etc.) are maintained (stored) until the data are then changed in the latch
circuits 61 and 62.
When the observer wears spectacles and closes the switch 60 to make the
inputs of the AND gates 66 and 67 High and the observer looks into the
finder, the output of the detecting unit 23 becomes High and therefore the
output of the AND gate 66 becomes High, and by the operation of the
operating portion 59, the lens is moved to effect optimum diopter
correction, and the data at this time are stored in the latch circuit 61.
Likewise, when in the state of naked eye, the observer closes the switch 60
and looks into the finder, the output of the detecting unit 23 becomes Low
and the output of the AND gate 67 becomes High. The operating portion 59
is then operated and data which provide appropriate diopter are stored in
the latch circuit 62, whereafter the switch 60 is opened.
Thus, even when during actual photographing, the observer does not perform
any special operation, if the observer looking into the finder wears
spectacles, the latch circuit 61 will be selected by the switch circuit
63, and if the observer is in the state of naked eye, the latch circuit 62
will be selected so that appropriate diopter can be obtained.
A timer circuit 75 inputs a trigger signal to the mono-multivibrator 50 on
the basis of a long time timer 70 or a short time timer 73 to thereby
effect the detection of the observation state at appropriate intervals.
The long time timer 70 intermittently transmits a trigger signal through an
OR gate 71. At this time, the detecting unit 23 receives the trigger
signal and when the beam of light applied from the light source 20 to the
observer side is not reflected by the observer side and no reflection
image is obtained, the detecting unit 23 judges that non-operation is
going on, and intermittently effects the detection of the observation
state.
Also, when the beam of light applied to the observer side is reflected by
the observer side and a reflection image is properly obtained by the image
sensor 54, the input to an AND gate 74 is made High through the amplifiers
56 and 57.
The AND gate 74 receives as an input a signal of relatively short intervals
from the short time timer 73 and therefore, a trigger signal is
transmitted at short intervals through the OR gate 71, and detailed
detection is effected by the detecting unit 23. This detailed detection is
effected until the input of the AND gate 74 becomes Low, that is, until
non-operation. Thereby, saving of electric power is achieved in the entire
apparatus.
In the present embodiment, diopter correction is automated as described
above and therefore, there is realized a camera which can always be
automatically changed over to diopter easy to see even during
photographing with or without spectacles being worn by the observer.
FIG. 5 is a schematic view showing the essential portions of Embodiment 2
of the present invention applied to a camera having visual axis detecting
means, and FIG. 6 is a schematic view showing the essential portions of
the finder optical system of FIG. 5.
In these figures, the reference numerals 9 and 51 designate eyepieces which
direct the beam of light from a pentagonal prism 10 to the observer's
eyeball 25.
A dichroic mirror 51a transmitting visible light therethrough and
reflecting infrared light is obliquely disposed in the eyepiece 51 and
serves also as an optical path divider.
The reference characters 20a, 20b and 20c denote light sources, each of
which comprises, for example, a light emitting diode or the like. The
reference numeral 22 designates an imaging lens.
The reference numeral 54 denotes an image sensor comprising photoelectric
element arrays disposed two-dimensionally. The image sensor 54 is disposed
so as to be conjugate with the vicinity of the pupil of the eyeball 25
which is at a predetermined location (the location of the general eye
point of an observer who does not use spectacles) with respect to the
imaging lens 22 and the eyepiece 51.
The reference numeral 57 designates an auxiliary lens disposed so as to be
removably insertable into an optical path. The auxiliary lens 57 is
adapted to be retracted out of the optical path and adjust diopter when it
is judged by a calculation processing unit which will be described later
that the observer is not using spectacles.
The reference numeral 59 denotes a calculation processing unit having a
processing portion 59a for processing the driving of the light sources 20
and a signal from the image sensor 54 to thereby find the observation
environment, a visual axis calculating portion 59b for finding the
observer's visual axis and gazing point on the basis of the signal from
the image sensor 54 processed by the processing portion 59a, and a memory
portion 59c for storing therein data for diopter correction. The imaging
lens 22, the light sources 20, the image sensor 54 and the processing
portion 59a each constitute an element of a detecting unit 53.
In the above-described construction, the elements 51, 20, 22, 59a, 59b,
etc. together constitute eyeball visual axis detecting means. Also, the
elements 51, 53, 59c, etc. together constitute diopter correcting means.
The reference numeral 1 designates a photo-taking lens, the reference
numeral 102 denotes a quick return (QR) mirror, the reference numeral 103
designates a display element, the reference numeral 104 denotes a focusing
screen, the reference numeral 105 designates a condenser lens, the
reference numeral 107 denotes a sub-mirror, and the reference numeral 108
designates a multipoint focus detecting device which selects a plurality
of areas in a photo-taking image field and effects focus detection.
The reference numeral 109 denotes a camera control device having the
functions of driving the display element in the finder, focus detection
calculation and lens driving.
In the present embodiment, part of the object light transmitted through the
photo-taking lens 1 is reflected by the QR mirror 102 and forms an object
image near the focusing screen 104. The object light diffused by the
diffusing surface of the focusing screen 104 is directed to an eye point E
through the condenser lens 105, the pentagonal prism 10 and the eyepieces
9, 51.
The display element 103 is, for example, a guest-host type liquid crystal
element of a two-layer type which does not use a polarizing plate, and
displays a distance measuring area (focus detecting position) in the field
of view of the finder.
Also, part of the object light transmitted through the photo-taking lens 1
is transmitted through the QR mirror 102, is reflected by the sub-mirror
107 and is directed to the aforementioned multipoint focus detecting
device 108 disposed in the bottom of the camera body. Further, on the
basis of the focus detection information of the selected position of the
multipoint focus detecting device 108 on the surface of the object, the
axial forward movement (or the axial reverse movement) of the photo-taking
lens 1 is effected by a photo-taking lens driving device, not shown,
whereby focus adjustment is effected.
In the visual axis detection of the present embodiment, infrared light
emitted from the infrared light emitting diodes 20a, 20b and 20c enters
the eyepiece 51 from above as viewed in FIG. 5, is reflected by the
dichroic mirror 51a and illuminates the observer's eyeball 25 located near
the eye point E. Also, the infrared light reflected by the eyeball 25 is
reflected by the dichroic mirror 51a and forms an image on the image
sensor 54 while being converged by the imaging lens 22. Also, the
processing by the calculation processing unit 59 is executed in accordance
with the software of a microcomputer.
The gazing point information detecting in the calculation processing unit
59 is first transmitted to the display element 103 and the multipoint
focus detecting device 108 through the camera control device 109. On the
display element 103, the location gazed at by the observer is displayed in
the finder of the camera, thus performing the function of confirming the
gazing point (focus detection point).
Also, the focus detection of the point gazed at by the observer is effected
in the multipoint focus detecting device 108 and focus adjustment is
effected to an object being gazed at.
FIG. 6 is a perspective view showing the essential portions of the visual
axis detecting means. The infrared light emitting diodes 20a, 20b and 20c
for illumination are used in one set of two to detect the distance between
the camera and the observer's eyeball, and in conformity with the posture
of the camera, the detection of the horizontal position is effected by the
infrared light emitting diodes 20a and 20b and the detection of the
vertical position is effected by the infrared light emitting diodes 20b
and 20c. Although camera posture detecting means is not shown in FIG. 6,
posture detecting means utilizing a mercury switch or the like is
effective.
FIGS. 7 and 8 are developed illustrations showing the optical path of the
detecting unit when the observer is observing by the naked eye and when
the observer is using spectacles, respectively, FIG. 9A is a schematic
illustration of the image of the eyeball of the observer using spectacles
which is formed on the image sensor 54, FIGS. 9B and 9C show output
intensities on the lines Yg and Yp, respectively, of the image sensor 54,
and FIGS. 10A and 10B are flow charts when detecting whether the
photographer is using spectacles.
When as shown in FIG. 8, the observer is using spectacles 84, part of the
illuminating light emitted from the infrared light emitting diodes 20a and
20b is reflected by a first surface 84a of the spectacles 84 (that surface
which is outer to the observer's eyeball) and enters the image sensor 54
through the imaging lens 22. It is FIG. 9A that shows the eyeball image
formed on the image sensor 54 at this time.
In FIG. 9A, the image formed by the light reflected by the first surface
84a of the spectacles 84 is shown as the reflection image of the
spectacles. Two such reflection images are usually created on the same
line because two infrared light emitting diodes 20a and 20b are used.
Another reflection image of the spectacles may be formed by the light
reflected by a second surface 84b of the spectacles 84, but it is omitted
in the present embodiment.
FIG. 9B shows the output intensity of the line Yg on which the reflection
image of the spectacles is created, and the reflection image of the
spectacles is detected with higher intensity than the reflection image of
the cornea because the reflectance of the spectacles is high.
Also, the radius of curvature of the first surface 84a of the spectacles 84
is usually greater than the radius of curvature of the cornea 81 and
therefore, the spacing between the two created reflection images of the
spectacles is greater than the spacing between the two reflection images
of the cornea.
In the present embodiment, as described above, the differences between the
reflection images of the spectacles and the reflection images of the
cornea, such as the intensity, the spacing and the imaged position, are
detected to thereby detect whether the observer is using spectacles, i.e.,
the observation state.
The flow of the detection of the observation state will now be described
with reference to the flow charts of FIGS. 10A and 10B.
When the detection is started, the line Yp for the creation of the
reflection images of the cornea and the line Yg for the creation of the
reflection images of the spectacles are first reset to zero (#100).
Further, the parameter y of line information and count parameter CNT are
reset to zero (#101).
The parameter y assumes the value of the number of the line on which it is
judged that the reflection images of the spectacles or the reflection
images of the cornea are created. Also, the count parameter CNT is the
number of the reflection images of the spectacles or the reflection images
of the cornea created on the same line.
Subsequently, the reading-out of the signal S(i, j) of the eyeball image
already stored in the memory of the calculation processing unit 59 is done
in the order of lines (#102), i and j are positive integers.
The reflection images of the spectacles and the reflection images of the
cornea are substantially equal to mirror surface reflection and are
therefore strong in intensity, and assuming that the threshold value of
the intensity by which the reflection images of the spectacles or the
reflection images of the cornea can be discriminated is So, if the signal
S(i, j) is smaller than the intensity So (#103), the reading-out of the
next signal S(i, j) is effected (#102). Also, if the signal S(i, j) is of
a magnitude greater than the intensity So (#103), it is judged that the
signal S(i, j) is the signal of the reflection image of the spectacles or
the reflection image of the cornea.
If at this time, the signal of the reflection image of the spectacles or
the reflection image of the cornea is not detected until that point of
time and the parameter y of the line information is zero (#104), the
parameter y representative of the line for creation of the reflection
images of the spectacles or the reflection images of the cornea is set to
y=i (#105).
Further, 1 is added to the count parameter CNT representative of the number
of the reflection images of the spectacles or the reflection images of the
cornea on the parameter y (=i) of the line information (#106) and the
position j at which the reflection images of the spectacles or the
reflection images of the cornea are created is recorded as Z(CNT)=j
(#107). The reading-out of the next signal (i, j) is then effected (#102).
Also, when the signal S(i, j) is of intensity So or greater (#103) and the
parameter y of the then line information is not zero (#104), the
discrimination of the value of the parameter y is effected. If the
parameter y of the line information coincides with the line number i which
is effecting the reading-out of the signal S(i, j) (#108), 1 is added to
the count parameter CNT representative of the number of the reflection
images of the spectacles or the reflection images of the cornea (#106) and
the position j at which the reflection images of the spectacles or the
reflection images of the cornea are created is recorded as Z(CNT)=j
(#107). The reading-out of the next signal S(i, j) is then effected
(#102).
On the other hand, if the parameter y of the line information does not
coincide with the line number i which is effecting the reading-out of the
signal S(i, j) when the discrimination of the value of the parameter y of
the line information has been effected (#108), it is judged that the
reading-out of the signal S of the parameter y of the line information has
already been terminated, and the discrimination of the count parameter CNT
is effected (#109). When the count parameter CNT is not 2 (when CNT=i),
only one signal S judged to be the reflection image of the cornea is
created on the parameter y of the line information and as a result, the
position information Z(1) already recorded is judged to be some ghost
which is not the reflection image of the spectacles and the reflection
image of the cornea.
The parameter y of the line information is then substituted for by a line
number i in which the reading-out of the signal S is being effected
(#110), and the position j at which the reflection images of the
spectacles or the reflection images of the cornea are created at that time
is recorded as Z(CNT)=j (#111). The reading-out of the next signal S (i,
j) is then effected (#102).
Also, if the count parameter CNT is 2 when the discrimination of the count
parameter CNT has been effected (#109), the spacing .DELTA.Z between two
positions at which the reflection images of the spectacles or the
reflection images of the cornea already recorded are created is found as
.DELTA.Z=.vertline.Z(1)-Z(2).vertline. (#112).
The spacing between two created images differs between the reflection
images of the spectacles and the reflection images of the cornea and
therefore, assuming that the threshold value of the spacing between the
images at which each image can be discriminated is .DELTA.Zo, if the
aforementioned spacing .DELTA.Z is smaller than the predetermined
threshold value .DELTA.Zo (#113), it is judged that the positions Z(1) and
Z(2) of the recorded images are the positions of the reflection images of
the cornea, and the positions Z(1) and Z(2) are set to Zp1=Z(1) and
Zp2=Z(2), respectively, as the positions of the reflection images of the
cornea (#114). Here, Zp1 and Zp2 are equivalent to Ze' and Zd' in FIG. 3B.
Further, the line Yp for the creation of the reflection images of the
cornea is set to Yp=y (#115).
Also, if the aforementioned spacing .DELTA.Z is greater than the
predetermined threshold value .DELTA.Zo (#113), it is judged that the
positions Z(1) and Z(2) of the recorded images are the positions of the
reflection images of the spectacles, and the positions Z(1) and Z(2) are
set to Zg1=Z(1) and Zg2=Z(2), respectively, as the position of Q3(#116).
Further, the line Yg for the creation of the reflection images of the
spectacles is set to Yg=y (#117).
Subsequently, whether both of the reflection image of the spectacles and
the reflection image of the cornea have been detected is judged. If the
product of Yg and Yp representative of the lines for the creation of the
respective images is zero, it is judged that one of the reflection image
of the spectacles and the reflection image of the cornea is not yet
detected (#118). So, the count parameter CNT is set to 1 (#119), and the
detection of the undetected image is continued (#110-#111, #102). If the
product of Yg and Yp representative of the lines for the spectacles and
the reflection image of the cornea is not zero, it is judges that both of
the reflection image of the spectacles and the reflection image of the
cornea have been detected (#118) and the detection of whether the
spectacles are used is terminated.
In the flow of this calculation, description has been made on the premise
that the observer is using spectacles, but when the observer is not using
spectacles, all image signals of the image sensor 54 are read out,
whereafter from the fact that the value of the line Yg for the creation of
the reflection image of the spectacles remains zero, the calculation
processing unit 59 can detect that the observer is not using spectacles.
Also, in the flow of this calculation, description has been made on the
premise that the number CNT of the reflection images of the spectacles or
the reflection images of the cornea created on the same line is 2 or less,
but the number CNT may be set to a value greater than 2 on the supposition
that some ghost or the like is created on the same line. At this time, the
distinction between the reflection image of the spectacles or the
reflection image of the cornea and the ghost is generally possible by
comparing the positions at which these images are created.
When the size of the reflection image of the spectacles or the reflection
image of the cornea created on the image sensor is large and a signal S
exceeding the intensity So is continuously detected, it is desirable that
the position of the centroid of the continuously detected signal S be
defined as the position of the reflection image of the spectacles or the
reflection image of the cornea.
Also, in the present embodiment, there has been shown an example in which
the distinction between the reflection images of the spectacles and the
reflection images of the cornea is made on the basis of the spacing
between the images, but since the reflection images of the spectacles are
greater in intensity than the reflection images of the cornea, distinction
may be made on the basis of the absolute value of the intensity of the
images.
Further, the positional relation between the lines on which the reflection
image of the spectacles and the reflection image of the eyeball are
created may be prestored in a memory portion and the positional relation
between the lines on which reflection images exceeding the intensity So
have been created may be compared with the positional relation between the
reflection image of the spectacles and the reflection image of the eyeball
recorded in the memory portion, whereby the detection of the observation
state may be effected, or detection may be effected by a combination of
these.
In the present embodiment, as described above, when the observation state
is detected by the detecting unit 53, the eyepiece 9 is moved by the
driving unit 17 on the basis of the date pre-stored in the memory portion
59c in conformity with the observation state to thereby adjust the diopter
of the finder.
While in the present embodiment, the adjustment of diopter is effected by
the eyepiece 9 being moved in the direction of the optical axis of the
finder optical system by the driving unit 17, this is not restrictive, but
rather, the diopter may be adjusted by a lens for diopter correction being
removably inserted into the optical path of the finder. For example, as
the lens for diopter correction, a lens of such refractive power that the
observer can obtain appropriate diopter by the naked eye when the lens is
located in the optical path of the finder may be pre-selected and disposed
and if the observation state detected by the detecting unit is naked eye,
the lens may be located in the optical path of the finder, and if the
observer is using spectacles, the lens may be retracted out of the optical
path, whereby the adjustment of diopter may be effected.
On the other hand, in the present embodiment, when the use of spectacles is
detected, the optical construction of the detecting unit 23 is adjusted
with the above-described correction of diopter.
Generally, the position of the eyes of an observer using spectacles for a
shortsighted person is ten and several millimeters farther than the
position of the eyes of an observer not using spectacles. Therefore, when
it is detected by the calculation processing unit 59 that the observer is
using spectacles, a pawl 11 mounted on a lens frame for holding the
auxiliary lens 57 is pulled in +2 direction by a driving device, not
shown, whereby the auxiliary lens 57 which is a concave lens is set in the
optical path.
As a result, the eyes of the observer using spectacles as the optical
system of the detecting unit and the image sensor 54 substantially
satisfies a conjugate relation through the dichroic mirror 51a to thereby
provide a good imaging state. As long as the auxiliary lens 57 is set in
the light receiving optical path of the detecting unit, the pawl 11 is
held in engagement with a pawl 12 mounted on the lens barrel of the
imaging lens 22.
Also, when it is detected by the detecting unit 53 that the observer is not
using spectacles, the pawl 12 releases the pawl 11 and as shown in FIG. 7,
the auxiliary lens 57 is set in a state retracted from the light receiving
optical path. Thereby, the construction of the optical system of the
detecting unit 53 is adjusted.
While in the present embodiment, there has been shown an example in which
the auxiliary lens 57 is removably inserted into the optical path of the
optical system of the detecting unit, whereby the optical system of the
detecting unit is adjusted so as to satisfy the conjugate relation between
the observer's eyes and the image sensor 54 of the detecting unit, this is
not restrictive, but the position of the imaging lens 22 constituting the
optical system of the detecting unit may be moved in the direction of the
optical axis to thereby effect said adjustment. In this case, the imaging
lens 22 may be comprised of a plurality of lenses, some of which may be
moved on the optical axis.
According to the present embodiment, diopter correction can be
automatically effected by a simple construction in which the various
elements (such as the light source and the light divider) of the visual
axis detecting means and the diopter correcting means are used in common.
Also, even when use is made of spectacles of which the diopter does not
match the observer, an appropriately preset correction value is used and
therefore, appropriate diopter is always obtained to thereby make the
apparatus easy to use.
FIG. 11 is a schematic view showing the essential portions of Embodiment 3
of the present invention. This embodiment differs from Embodiment 1 of
FIG. 1 in that the light emitting portions of the light source are
disposed in predetermined spaced apart relationship with each other and
the difference (differential) information between the reflection images of
the respective light emitting portions is used to detect observation
information, and is substantially the same as Embodiment 1 in the other
points.
In FIG. 11, the reference characters 80a and 80b designate iRLEDs which
illuminate the observer's eyeball 25 at an angle differing from that of
iRLEDs 20a and 20b.
In the present embodiment, the differential information of the reflection
image based on the iRLEDs 20a, 20b and the reflection image based on the
iRLEDs 80a, 80b is obtained to thereby find the curvature of the
reflecting surface. Thereby, whether the observer is using contact lenses
can also be detected with good accuracy.
In each of the above-described embodiments, the adjustment of diopter
conforming to the detected observation state may be that in which diopter
correction is not effected (is returned to ordinary diopter, i.e., diopter
at which any observer of normal eyesight can appropriately observe).
Also, in the above-described embodiments, when the use of spectacles has
been detected, the finder optical system may be adjusted to preset diopter
and also, at least a portion of the finder optical system may be moved and
the distance from the eyepiece to the eye point may be set so as to become
longer than that in the case of the naked eye.
According to the present invention, there can be achieved an optical
apparatus having diopter correcting means in which the observation state
of an observer looking into an optical system is detected and at least a
portion of the optical system is moved on the basis of the observation
state, whereby the simplification of the entire apparatus is contrived and
yet appropriate diopter correction can be easily effected even in
different observation states.
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